Semiconductor device and method for manufacturing same

ABSTRACT

A method of making a semiconductor chip  1  having a first electrodes  11, 12  on main surface la thereof, a second electrode  13  made of a conductive resin electrode having a base portion  131  in contact with a surface  1   b  opposite to the main surface  1   a  of the semiconductor chip  1,  and a side portion  132  extended from one end portion of the base portion  131  in the direction toward the main surface  1   a  of the semiconductor chip  1,  wherein an end part of the side portion  132  of the second electrode  13  is exposed on the same side as the first electrodes  11, 12.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a semiconductor device and to amethod for manufacturing a semiconductor device, and more particularlyit relates to a compact, thin semiconductor device, and to a method ofmanufacturing a semiconductor device with high productivity.

[0003] 2. Background of the Invention

[0004] In recent years, in response to the demand for electronicequipment with sophisticated functions, compactness, light weight, andhigh speed, a variety of forms of semiconductor devices are beingdeveloped. For example, this is not even limited to integrated circuits,there being a demand for compactness and light weight in such discretecomponents as diodes and transistors as well.

[0005] For example, in a transistor of the past, there has been aconfiguration in which electrodes for outputting signals have beenprovided on a main surface and another electrodes have been provided ona surface that is opposite the main surface of the chip 1. In contrastto this approach, in response to recent demand for compactness insemiconductor devices, there have been attempts to achieve compactnessby providing a plurality of electrodes on a single surface of thesemiconductor chip.

[0006]FIG. 5 shows a cross-section view of a transistor of the pastwhich has a plurality of electrodes on a single surface of thesemiconductor chip. In this semiconductor device of the past, as shownin FIG. 5, on one surface of a semiconductor chip 1 are provided a gateelectrode (or base electrode) 41, a source electrode (or emitterelectrode) 42, and a drain electrode (or collector electrode) 43.

[0007] In a transistor such as shown in FIG. 5, however, the followingproblem occurs.

[0008] In general, a transistor has characteristics such that, byapplying a voltage to the gate electrode, the value of resistancebetween the drain electrode and the source electrode is reduced (thisresistance value being referred to hereinafter as the on resistance). Inthis case, in order to cause a prescribed current to flow in the drainelectrode, a voltage is applied to the drain electrode, this beingsmaller the smaller the on resistance is. While the power consumption ofeach transistor is not that large, because a large number of suchtransistors are provided in the circuit product, it is desirable thatthe power consumption of each transistor be made smaller. That is,because the power consumed to drive a transistor is smaller the smallerthe on resistance is, it is desirable to make the on resistance of thetransistor small.

[0009] The resistance value r of an electrode is generally determined asp=l/S (where p is the resistivity, l is the length of the electrode, andS is the cross-sectional area) In a semiconductor device of the pastsuch as shown in FIG. 5, if the width W′ of the drain electrode 43 ismade larger, the resistance value r, which is the on resistance, becomessmaller. However, the drain electrode 43 is formed of a semiconductorsubstance formed by a diffusion process as described above, the only wayto make the cross-sectional area, or the width W′ of the drain electrode43 large, is to make the semiconductor chip 1 larger. That is, in asemiconductor device of the past such as shown in FIG. 5, it is notpossible to make the semiconductor chip itself small and obtain asufficiently large on resistance. Thus, in a conventional semiconductordevice, in the case in which the drain electrode and the sourceelectrode are formed on one and the same surface and in which a drainelectrode is formed in proximity to the gate electrode and sourceelectrode, there was the problem of not being able to achieve a smallenough overall size.

[0010] Accordingly, it is an object of the present invention to solvethe above-noted problem in the prior art, by providing a compact, thinsemiconductor device. It is a further object of the present invention toprovide a method for manufacturing a semiconductor device featuring goodproductivity.

SUMMARY OF THE INVENTION

[0011] In order to achieve the above-noted objects, the first aspect ofthe present invention is a semiconductor device comprising, asemiconductor chip having a first electrode on a main surface thereof, asecond electrode made of a conductive resin electrode having a baseportion in contact with a surface opposite to the main surface of thesemiconductor chip, and a side portion extended from one end portion ofthe base portion in the direction toward the main surface of thesemiconductor chip, and an end part of the side portion of the secondelectrode is provided over the main surface of the semiconductor chip.

[0012] In the present invention, the second electrode has a bending partformed between the base portion and the side portion at a substantiallyright angle.

[0013] In the present invention, the side portion of the secondelectrode is provided between a first insulating resin which seals atleast the main surface of the semiconductor chip and a second insulatingresin which seals surfaces other than the main surface of thesemiconductor chip.

[0014] In the present invention, the side portion of the secondelectrode is provided along one side surface of the semiconductor chip.

[0015] The second aspect of the present invention is a method ofmanufacturing a semiconductor device comprising; a first step of forminga plurality of first electrodes 10 (11, 12) on a main surface 0 a of asemiconductor wafer 0, a second step of affixing the semiconductor wafer0 to a first tape 29 so that the first electrodes 10 are facing up, athird step of dicing the semiconductor wafer 0 in one direction alongA-A′ in FIG. 2(c), so as to form a plurality of semiconductor units 111having a plurality of semiconductor chips 1, a forth step of expandingwidth of first grooves 30 that are formed when the dicing in the thirdstep is performed, a fifth step of orientating the plurality ofsemiconductor units 111 so that surfaces 1 a on which the firstelectrodes 10 are provided are facing up, and arranging the plurality ofsemiconductor units 111 on a flat sheet 31 so as to form second grooves18, a sixth step of covering surfaces 1 a of the semiconductor units 111and burying the second groove 18 with an insulating resin 14 andhardening the insulating resin 14, a seventh step of affixing thesemiconductor units 111 to a second tape 32 so that the first electrodes10 are facing down, a eighth step of dicing the semiconductor formed inthe sixth step in a direction parallel to the second groove 18, atsubstantially the center of said second groove 18, so as to form thirdgrooves 33, a ninth step of covering the semiconductor formed in theeight step and burying the third grooves 33 with a conductive resin 16,a tenth step of dicing the semiconductor formed in the ninth step alongboundaries formed between the conductive resin 16 and the insulatingresin 14 so as to form second electrodes 13, a eleventh step of dicingthe semiconductor formed in the tenth step in a direction perpendicularto the boundaries, so as to form a plurality of semiconductor devices 19having the first electrode 10 and the second electrode 13, and formingforth grooves 34 between the semiconductor devices 19, a twelfth step ofexpanding the forth grooves 34, a thirteenth step of covering thesemiconductor devices 19 formed in the eleventh step with an insulatingresin 15, and burying the forth grooves 34 with the insulating resin 15,and hardening the insulating resin 15, and a fourteenth step of dicingto form separate semiconductor devices 4 having a prescribed number ofthe semiconductor chips 1.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1(a) and FIG. 1(b) are cross-section views of a semiconductordevice according to the present invention, and FIG. 1(c) is aperspective view of a semiconductor device according to the presentinvention.

[0017] FIGS. 2(a) to (d) are drawings showing the manufacturing processsteps for a semiconductor device according to the present invention.

[0018] FIGS. 3(a) to (f) are cross-section views showing themanufacturing processes for a semiconductor device according to thepresent invention, and FIG. 3(g) is a cross-section view of asemiconductor device according to the present invention.

[0019]FIG. 4(a) is a drawing showing an another embodiment of thepresent invention, and FIG. 4(b) is a perspective view of the presentinvention in FIG. 4(a).

[0020]FIG. 5 is a cross-section view showing a semiconductor device of aprior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Embodiments of a semiconductor device and a method formanufacturing a semiconductor device according to the present inventionare described in detail below, with reference made to relevantaccompanying drawings. It will be understood, however, that the presentinvention is not restricted to the embodiments described herein, and cantake on other various forms, within the spirit of the present invention.

[0022]FIG. 1 is a cross-section view and a perspective view of asemiconductor device according to the present invention.

[0023]FIG. 2 is a drawing showing the manufacturing process steps for asemiconductor device according to the present invention.

[0024]FIG. 3 is a cross-section view showing the manufacturing processesfor a semiconductor device according to the present invention.

[0025]FIG. 4 is a cross-section view and a perspective view showing ananother embodiment of the present invention.

[0026] A semiconductor device according to the present invention is adiscrete semiconductor device such as a transistor, a diode, or avertical-type MOSFET or the like, which, as shown in FIG. 1(a), has twotypes of electrodes 10 (11, 12) having differing characteristics on amain surface of a semiconductor chip 1, and a drain electrode 13(collector electrode) which is a conductive resin electrode formed by abase portion 131 and a side portion 132. That is, the semiconductordevice has a drain electrode 13 formed by a base portion 131 in contactwith a surface 1 b on the opposite side from the main surface 1 a, and aside portion 132 formed by extension from one end of the base portion131 in the direction toward the main surface 1 a, the surface 1 b of thesemiconductor chip 1 and the side surfaces of the side portion 132 ofthe drain electrode 13 being sealed by insulating resins 14 and 15, andthe end parts of the two types of electrodes 10 and the end part of theside portion 132 being aligned on the same plane 1 a. That is, theextension direction of the end parts of the two types of electrodes 10and the end part of the side portion 132 of the drain electrode 13 aremade the same direction, and side surfaces other than the plane ontowhich the end parts of the two types of electrodes 10 and the end partof the drain electrode 13 made of a conductive resin are aligned aresealed with the insulating resins 14 and 15. The direction of extensionof the ends of the two types of electrodes 10 and the end part of thedrain electrode 13 can be said to be the extension direction for makingconnection to an external component outside the semiconductor device.

[0027] The semiconductor wafer 0 is already diffused, and onto the mainsurface thereof are formed two types of electrodes 10. In the presentinvention, the two types of electrodes 10 are a gate electrode (baseelectrode) 11 and a source electrode (emitter electrode) 12, these beingprovided as metal bumps of gold or the like, for the purpose ofconnection between the semiconductor chip 1 and an external component.The main surface as used herein is the surface of the semiconductor chip1 on which the gate electrode 11 and the source electrode 12 areprovided.

[0028] In the present invention, the drain electrode 13 is a conductiveresin electrode made from a conductive resin, formed by curing a copperpaste or silver paste, which is thermally curable. The base portion 131of the drain electrode 13 is in contact with a surface 1 b on theopposite side from the main surface 1 a of the semiconductor chip 1, onwhich the electrodes 10 are formed. The side portion 132 of the drainelectrode 13 makes contact with the insulating resin 14 and is acontinuation of one end part of the base portion 131, extending in thedirection of the main surface 1 a, substantially perpendicularly withrespect to the base portion 131. The phrase “continuation of one endpart of the base portion 131” herein refers to a bending of the baseportion 131 at a substantially right angle from one end of the baseportion 131. The phrase “continuation of one end part of the baseportion 131, extending in the direction of the main surface 1 a,substantially perpendicularly with respect to the base portion 131”refers to formation of the base portion 131 and the side portion 132 soas to make an approximate L-shape therebetween, the side portion 132extending in the direction of the main surface of the semiconductor chip1, substantially being provided in parallel with one side surface of thesemiconductor chip 1.

[0029] The insulating resins 14 and 15, as described above, seal thesurface 1 b of the semiconductor chip 1 and the drain electrode 13. Inother words, the insulating resins 14 and 15 seals all surfaces of thesemiconductor chip except 1 for end parts of the electrode 10 and theend part of the drain electrode 13 made of a conductive resin. Forexample, this is made of a highly conductive resin such as an epoxyresin or the like. The surface 1 b of the semiconductor chip 1, as usedherein, refers to the a surface other than a part in which thesemiconductor chip 1 is in contact with the drain electrode 13, and thesurface 13 a of the drain electrode 13, as used herein, refers to asurface other than a part at which the drain electrode 13 is in contactwith the semiconductor chip 1. As described above, although a sidesurface other than a part in which the semiconductor chip 1 is incontact with the drain electrode 13 is sealed by the insulating resins14 and 15, the electrodes are formed so as to be exposed from theinsulating resin 14 formed on the semiconductor chip 1, so as to make itpossible to make a connection between the ends of the two types ofelectrodes 10, and the end part of the side portion 132 of the drainelectrode 13 and an external component. That is, the end parts of thetwo types of electrodes 10, and the end part of the side portion 132 ofthe drain electrode 13 are not covered by the insulating resin 14. Theend part of the side portion 132 of the drain electrode 13, as usedherein, refers to the end part of the side portion 132 formedcontinuously from the base portion 131.

[0030] As described above, in a semiconductor device according to thepresent invention, the end parts of the two types of electrodes 10 andthe end part of the side portion 132 of the drain electrode 13 arealigned on one and the same plane and, because it is possible on one andthe same plane to make connection between the gate electrode 11 and thesource electrode 12, which are the two types of electrodes 10, and thedrain electrode 13 and an external component outside the semiconductordevice, it is possible to achieve a small overall size and thinness. Thedrain electrode 13 is formed of a conductive resin, and because thisresin has a resistivity that is smaller than a drain electrode of asemiconductor device of the past, even if the width W of the sideportion 132 of the electrode 13 in FIG. 1 is made small, it is possibleto achieve an electrode with a sufficiently small resistance value,thereby enabling the achievement of a compact semiconductor device witha reduced resistance between electrodes.

[0031] Next, a method of manufacturing a semiconductor device such asshown in FIG. 1 is described below, with reference being made to FIG. 2and FIG. 3. First, the manufacturing process of a semiconductor chip 1used in the present invention will be described, with reference made toFIG. 2.

[0032] First, a plurality of electrodes 10 (gate electrode 11 and sourceelectrode 12), which are made of metal bumps, are formed on a diffusedsemiconductor wafer 0 (refer to the plan view of the semiconductor wafer0 shown in FIG. 2(a)). An enlarged perspective view of the semiconductorwafer 0 of FIG. 2(a) is shown in FIG. 2(b). A gate electrode 11 and asource electrode 12 are provided at each prescribed location on thesemiconductor wafer 0, these two types of electrodes 10, consisting of agate electrode 11 and a source electrode 12, and a semiconductor chip 1(obtained in a subsequent process step, refer to FIG. 3(g)) ultimatelyforming one device.

[0033] Next, dicing is done from the cross-section A-A′ of thesemiconductor wafer 0 shown in FIG. 2(b), so as to cut the semiconductorwafer 0 in parallel in one direction only, thereby forming a pluralityof semiconductor chips 111 arranged in parallel, via a first groove 30formed by the dicing. FIG. 2(c) shows a plan view of the semiconductorwafer 0 in this process step. Then, expansion of the semiconductor chip111 is done in the direction of broadening the first groove 30, therebybroadening the mutual spacing B between the semiconductor chips 111(refer to FIG. 2(d)).

[0034] Next, the manufacturing process of the present invention usingthe semiconductor chip 1 obtained from the process steps shown in FIG.2, will be described, with reference being made to FIG. 3. FIG. 3 is across-section view in the direction of arrow C in FIG. 2(d). First, thesemiconductor chips 111 obtained by the process shown in FIG. 2(d) areoriented so that the surface on which the two types of electrodes 10 areprovided is facing up, and these are arranged on a flat sheet 31 so asto form the mutual spacing 18 between the semiconductor chips 111, afterwhich an insulating resin 14 is applied to the semiconductor chip 1 andcured (refer to FIG. 3(a)). When this is done, the insulating resin 14is filled so that the end parts of the two types of electrodes 10 areexposed.

[0035] Next, the semiconductor chip 1 is removed from the flat sheet 31,and the semiconductor chip 111 is affixed to a tape 32 so that the twotype of electrodes 10 are facing down, and dicing is done from the uppersurface (surface on the opposite side from the surface on which twotypes of electrodes 10 are provided) in parallel with the second groove18 and at substantially the center between the semiconductor chips 111sealed by the insulating resin 14, so as to form a third groove 33between the insulating resin 14 (refer to FIG. 3(b)). Then, a conductiveresin 16 is applied onto the second groove 33, the entire surface of thesemiconductor chip 111, and the insulating resin 14 (refer to FIG. 3(c))

[0036] Then, dicing is done from the cutting plane D (boundary betweenthe conductive resin 16 and the insulating resin 14), and dicing is donebetween the semiconductor chips 111 in a direction perpendicular to thecutting plane D, thereby forming a plurality of semiconductor devices 19having at least one semiconductor chips 1, two types of electrodes 10and one drain electrode 13 made of the conductive resin 16, with forthgrooves 34 formed between the devices 19 (refer to FIG. 3(c) to FIG.3(e)). Then, the overall device shown in FIG. 3(e) is expanded so as toexpand the forth groove 34, after which insulating resin 15 is filledinto the third groove 34 and onto the drain electrode 13 and allowed tocure (refer to FIG. 3(f)). Finally, cutting is done (at the cuttingplane E-E′) so as to include a prescribed number of devices, therebyresulting in a semiconductor device according to the present invention(refer to FIG. 3(g)). As shown above, in a method for manufacturing asemiconductor device according to the present invention, because it ispossible to fabricate a large number of semiconductor devices using aplurality of semiconductor chips 1 obtained from the semiconductor wafer0, it is possible to improve productivity. From the above, it ispossible to reduce the cost of manufacturing a semiconductor device.

[0037] The semiconductor device manufactured by the process stepsillustrated in FIG. 2 and FIG. 3 is shown in FIG. 1 (b) and FIG. 1(c).FIG. 1(b) is a cross-section view showing the same type of semiconductordevice as FIG. 2(g), and FIG. 1(c) is a perspective view of thesemiconductor device. The semiconductor device of the present inventionobtained by the above-noted manufacturing processes has a long side X, ashort side Y, and a height Z that are one to three times the long sideX′, the short side Y′, and the height Z′ of the semiconductor chip.Because of this, it is possible to obtain a semiconductor device that ismore compact than a conventional semiconductor device.

[0038] In the processes shown in FIG. 2 and FIG. 3, by cutting thedevice 19 that includes one semiconductor chip 1, each device includesone gate electrode 11, one source electrode 12, and one drain electrode13. As shown in FIG. 4(a), by cutting the semiconductor device along thecutting plane F, it is possible to obtain a semiconductor device 41 thatincludes a plurality of devices 4. While FIG. 4(b) shows the example ofa unit in which the semiconductor chips 1 are arranged in a line, thereis no restriction to arrangement of the semiconductor chips 1, and bychanging the position of the cutting plane F, it is possible to achievean arrangement configuration suitable to the application. Thus, bychanging the number of semiconductor chips 1 including in one unit andthe arrangement configuration thereof to suit requirements, it ispossible to fabricate a semiconductor device having a desired number ofsemiconductor chips and desired unit configuration, thereby enabling theachievement of a semiconductor device having a configuration that isoptimized for an application.

[0039] According to the present invention as noted above, it is possibleto make a connection between the two types of electrodes and theconductive resin electrode and external components outside the device onone surface, thereby enabling the achievement of a small overallsemiconductor device size. The conductive resin electrode is made of aconductive resin, which has a resistivity that is lower than that of thedrain electrode of a conventional semiconductor device, so that even ifthe width of the side portion of the electrode is small, it is possibleto achieve an electrode with a sufficiently small resistance value,thereby enabling the achievement of a compact semiconductor device witha reduced resistance between electrodes.

What is claimed is:
 1. A semiconductor device comprising; asemiconductor chip having a first electrode on a main surface thereof, asecond electrode made of a conductive resin electrode having a baseportion in contact with a surface opposite to said main surface of saidsemiconductor chip, and a side portion extended from one end portion ofsaid base portion in the direction toward said main surface of saidsemiconductor chip, and an end part of said side portion of said secondelectrode is provided over said main surface of said semiconductor chip.2. A semiconductor device according to claim 1, wherein said secondelectrode having a bending part formed between said base portion andsaid side portion at a substantially right angle.
 3. A semiconductordevice according to claim 1, wherein said side portion of said secondelectrode is provided between a first insulating resin which seals atleast said main surface of said semiconductor chip and a secondinsulating resin which seals surfaces other than said main surface ofsaid semiconductor chip.
 4. A semiconductor device according to claim 1,wherein said side portion of said second electrode is provided along oneside surface of said semiconductor chip.